Fast idle + engine management lights on

[b6qsport]

Hi, My first post - been lurking a while and learning lots.

Got a problem with my 2003 1.8t Quattro and would be interested in people's opinions. Yesterday while driving home I felt a slight hesitation while at speed but nothing else happened and car carried on. On stopping at some traffic lights I noticed the idle speed was 1200 rather than the usual 800 or so. Revved it but no change so stupidly turned the engine off to see if that reset it. Engine really struggled to start (as if flooded) and when I finally got it going the EPC warning was on in the dash and it was still idling at 1200. Tried this again when I got home and the same thing happened and in addition the other engine management light came on. Tried again this morning with a cold engine and it starts first time with the idle easing back to 800 as normal. The EPC light was off but the other engine management light is now permanently lit.

I'm guessing this is a temperature sensor issue but a little confused as to why the idle has gone back to 800 this morning - if the sensor is broken then why is it not staying at 1200? Does anyone have any other ideas?

[kite]

Get a fault code scan.
It could be a sticky throttle body.

[RickT]

or it could be a leaking vacum hose, which is over rev'ing it to make sure it does not stall...

Rick

[b6qsport]

Thanks for the suggestions - the fault code indicates it's the engine speed sensor. It's being replaced today so hopefully that will be an end to it.